NEET Chemistry The p-Block Elements (XII) Questions Solved


Which of the following orders is correct?

(1) SbH3>NH3>AsH3>PH3 – Boiling Point

(2) NH3>PH3>AsH3>SbH3  – Thermal Stability

(3) NH3>PH3>AsH3>SbH3  – Basic Character

(4) NH3>PH3>AsH3>SbH3  – Bond Angle

(A) (1), (2) and (3) only                             (B) (2), (3) and (4) only

(C) (1), (3) and (4) only                             (D) (1), (2), (3) and (4).

(C) (1) NH3  has higher boiling point than AsH3 and PH3  on account H-bonding. SbH3 has highest boiling point on account of highest molecular weight.

(2)  As the size of element increases, the strength of M–H bond decreases and thus stability decreases.

(3) Basicity decreases down the group. (Drago rule).

(4) HEH angle ° : NH3 = 107.8; PH3 = 93.6, AsH3 = 91.8; SbH3 = 91.3.

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